An epidemiological study of talc-related respiratory morbidity among employees of a rubber industry in Shiraz-Iran

OBJECTIVES: The main purpose of this study was to assess and characterize the pulmonary reactions associated with occupational exposure to talc dust. METHODS: Ninety-seven talc workers and 110 unexposed employees as the reference group were randomly selected from a local rubber industry. Standardized respiratory questionnaires were administered to the subjects, they underwent chest X-ray and were examined by a specialist for any possible respiratory abnormality to be diagnosed. Furthermore, pulmonary function tests (PFTs) were measured just before and after the work shift. Moreover, to assess the extent to which workers had been exposed to talc dust, using standard methods, inhalable and respirable dust concentrations were measured in different dusty worksites. RESULTS: The average (mean +/- SD) age (years), weight (kg), height (cm) and duration of exposure to talc dust (years) for the exposed group were 35.8 +/- 6.75, 73.1 +/- 9.2, 172.3 +/- 5.9 and 11.79 +/- 5.3, respectively. The corresponding values for the non-exposed group were 36.1 +/- 6.87, 73.36 +/- 8.1, 173.2 +/- 5.7 and 0 +/- 0, respectively. Atmospheric concentrations of inhalable and respirable talc dust were estimated to be 41.8 +/- 23.52 and 19.8 +/- 8.04 mg/m(3) (mean +/- SD), respectively. Talc exposed subjects had a significantly higher prevalence of respiratory symptoms. Similarly, PFTs revealed that exposure to this lubricating agent was associated with significant decreases in the mean percentage predicted of vital capacity (VC), forced vital capacity (FVC) and forced expiratory volume in the first second (FEV(1)). Likewise, there was a general tendency for VC, FVC and FEV(1) to decrease as estimated cumulative exposure (years worked) increased. Moreover, there was an acute reduction in some parameters of pulmonary function such as VC, FVC and FEV(1), over the work shift. Chest radiographs of exposed workers showed that pneumoconiosis profusions were between p 0/0 and p 2/1 according to the ILO 1980 chest X-ray classification. CONCLUSIONS: These results that are in full agreement with our preliminary observations, support the notion that occupational inhalation exposure to talc is associated with both acute and chronic respiratory disorders and induces bronchitis and interstitial lung disease.